1. Field of the Invention
This application is directed to arylamine/hindered phenol, acid anhydride and thioester-derived reaction products as multifunctional antioxidant, antiwear and rust-inhibiting additives for lubricants and fuels and to compositions containing same.
2. Description of Related Art
The use of arylamines and hindered phenols for their antioxidant properties when incorporated into oleagenous compositions is well known in the lubricant art. The use of sulfur compounds such as thioesters, sulfurized olefins, sulfurized oils and sulfurized fatty acid esters is well known for their antioxidant properties as well as their antiwear and EP characteristics in a variety of products. It is also known that the antirust and antiwear characteristics can, on occasion, be related to common structural features. Antiwear additives may also be good rust inhibitors if the key functional groups are synergistically united. It is believed that antioxidancy can be enhanced with a synergistic combination of sulfur-containing compounds, hindered phenols and arylamines.
This unique class of compounds clearly demonstrates promising antioxidant, rust-inhibiting and antiwear characteristics in lubricants. The syntheses and application of this family of compounds in lubricant compositions have not been disclosed elsewhere and are, therefore, novel. Similar performance advantages are expected with the use of these compositions in hydrocarbon, oxygenated, or mixed fuel formulations.